The invention relates to the cure of epoxy resins. In one aspect, the invention relates to acceleration of aliphatic amine cure of epoxy resins.
Certain common accelerators for aliphatic amine cure of epoxy resins, such as alcohols, phenols and carboxylic acids, tend to give a relatively low degree of acceleration. Others, such as calcium nitrate tetrahydrate, overcome this problem but must be added as third components, whether or not dissolved in a solvent. Calcium nitrate, when dissolved in an epoxy resin, tends to cause advancement of the resin and to lose activity on storage. If dissolved in the amine curing agent, it tends to give a copious precipitate in the presence of traces of water (from atmospheric moisture or the water of hydration of calcium nitrate tetrahydrate).
It is therefore an object of the invention to provide an epoxy resin/amine system which exhibits accelerated cure. It is a further object of the invention to provide an aliphatic amine-cured epoxy resin system having an amine-soluble accelerator component.